A new paper by researchers at the Harvard School of Public Health (HSPH) suggests that positive psychological well-being may reduce the risk of heart attacks, strokes and other adverse cardiovascular events.

Many previous studies have shown that negative mental states, like depression, anger and hostility, can be harmful to heart health. But the new report — an analysis of studies from the last 15 years — is the first large, systematic review of data on positive mood and cardiovascular outcomes.

Not suffering from depression is not the same as having a high level of optimism, note the authors of the study, published Tuesday in the journal Psychological Bulletin. “Even if a person doesn’t have depression or anxiety, that only puts them at a neutral point,” says study author Julia Boehm, a research fellow in the department of society, human development and health at HSPH. “That doesn’t mean they have happiness and optimism.”

After reviewing more than 200 studies published in two scientific databases, PubMed and PsycINFO, the authors found that optimism, life satisfaction and happiness were associated with reduced risk of cardiovascular disease and its progression. “For example, the most optimistic individuals had an approximately 50% reduced risk of experiencing an initial cardiovascular event compared to their less optimistic peers,” Boehm said in a statement.

The association remained true regardless of factors like age, socioeconomic status, smoking and body weight. “Even if a person is overweight, smokes a lot and has high cholesterol, they can still benefit from positive emotions. It is something unique about well-being itself,” says Boehm.

Why exactly positivity may benefit the heart isn’t clear, but the researchers suggest that optimistic people may be more motivated to treat their bodies well. “Having a purpose in life motivates people and gets them thinking about the future and how they can structure their lives. They want to get out and do things. They are not sitting at home watching TV,” says Boehm.

“We found that if you have a positive disposition you’re more likely to exercise, eat well and get enough sleep at night. This can have positive biological effects in terms of inflammation, cholesterol, blood pressure and lipids,” says Boehm. “Engaging in healthier behaviors can lead to healthier bodily functions.”

If further research supports the current findings, the authors hope it will allow for improved heart-disease prevention and treatment methods. “We are finding that bolstering psychological strength might be a useful target for future intervention. We don’t just want to fix what is wrong with someone, but we want to improve their overall well-being.”

“I think we can identify people who are socially isolated and pessimistic and find a role for cognitive therapy,” says Dr. Nieca Goldberg, an American Heart Association spokesperson and director of the Joan H. Tisch Center for Women’s Health at New York University Medical Center. “When dealing with cardiovascular patients, we often see these negative emotions. Stress management and physical activity can help boost moods.”

For now, the authors recommend people “treat” themselves by focusing on the little things in life that are meaningful to them and make them happy.